232 upgrade to 258?

Why the 258 sump? Economics. Same sump bolted to the 232 and 258, why make two different ones? The bumps on the left side do noting in the 232, but do no harm either. That's why I questioned the two intakes, but AMC may have used two different suppliers anyway, or they made enough manual steering cars that the 3-5 cents of aluminum for the PS mounts made a difference to the bean counters... or maybe the engineers just didn't like the looks of bosses sticking out on the intake with nothing attached. The sump doesn't easily show like the intake does.

The only way to determine if you have a 258 is to measure the stroke. Get a piece of stiff wire and run it in a spark plug hole. Run the piston down to the bottom then mark the wire. Run piston to top and mark again. Make sure you use the same reference point when marking. Measure between marks. Is it closer to 3.5" or closer to 3.895"? Shorter is 232. Your measurement should be slightly more than the actual stroke due to the angle. If the measurement is anything less than 3.895" it's a 232. The 258 will measure right at or over 4" using this method.

You are correct, pre 1979 casting numbers are shared between the 232 and 259. I found one  casting number in my list that is in the 232 section that isn't in the 258, but that is likely a mistake -- it is probably a 70 only number, or should be in the 258 listing also. I have it listed as 70-72, bit it can't be over that range since the 71 block is taller. But then some of the short blocks were likely still cast for a couple years to allow for warranty replacements. If a block cracked or was otherwise damaged in a new enough car the internal parts would be changed over. Makes no monetary sense now, but back then the dealer and/or factory probably saved a bit by doing it that way. Labor costs in the US have skyrocketed until it's not worth the effort any more, that tells you something about how labor costs have gone up right there!

What about a 4.0L from an XJ?

So I guess there was at least two different intakes. I sure wouldn't have made two!

Yes, the Jeep oil pans are deeper, so you'd need the pickup tube as well. He'll also need a 258 oil pan... maybe.

Wizzle, look on the left side of the oil pan where it's close to the block. Is the pan smooth, or are there some "bumps" along the side of the pan? The "bumps" are there to clear the 258 rods. I believe AMC made only one pan, but that may have only been for the last few years of the 232.  If you have the "bumps" in your pan you can use the pickup tube and pan from your engine. If not, you might be able to dent the pan with a hammer to clear the rods rather than ship one over. A 4.0L pan and pickup tube will work to, I think. Those you can find over there.

farna wrote: Check the AMC clubs in Australia. Remember, a 258 from an AMC car will work just as good as one from a Jeep. Wranglers had the 258 up to 1989 as well, not just CJs. I don't think they sold many of the full size Jeep trucks down there, is any.

 

billd wrote: Being that's a 74 Jeep, I"m with the fellow from Texas - a 258 would be a drop-in. no modifications, mounts and bell housing would be in the right places. Sometimes you need to watch for power steering bracket mounting - I've seen intakes with different holes and placements, but can't recall the details. but that's a simple thing. Yep, he said it well.

Cheers Bill.
I'll begin the hunt (locally) for a complete 258 then...
Failing that, I'll start to look further abroad (US) for the components to upgrade.
Do you mean the power steering pump bracket? Was power steering standard on all 258 equipped vehicles? I eventually had to upgrade to power steering after finding it too difficult to source manual steering parts for a right hand drive. The RH manual steering boxes seem to be as rare as hen's teeth.